The last few days have seen the round of 16 take place, with Carla Suárez Navarro making the cut.
Sloane Stephens did not, falling in straight sets in her fourth round match against Serena Williams.
Williams still hasn't dropped a set the whole tournament - she hasn't even been pushed beyond 6-4.
Sister, fellow former US Open champion, doubles partner and more - Venus Williams cheered her on.
Sunday night also saw the biggest upset of the tournament, as Ekaterina Makarova took out the No.3.
Agnieszka Radwanska was looking to complete her Grand Slam quarterfinal set, but not this time.
Meanwhile on Arthur Ashe Stadium, Jelena Jankovic was struggling with on-song No.5 seed Li Na.
Li won seven straight games from 5-3 in the first set to cruise past a bewildered Jankovic, 63 60.
Roberta Vinci snuck her win in on Monday morning before the rain fell on Flushing Meadows...
After that Flavia Pennetta became the next to win on Labor Day, pulling off quite the shocker.
Simona Halep had been the form player coming into the tournament, but Pennetta got her in straights.
And Daniela Hantuchova also got to the quarters. Victoria Azarenka and Ana Ivanovic were postponed.
The stars kept coming out to the Open over the last few days, including famous voice Estelle.
And Kelsey Grammer - of Cheers and Frasier fame - was also in attendance over the weekend.
Billie Jean King and Martina Navratilova met some young WTA stars at their Power Hour group session.